Baby gene map may cut diagnosis

In 2 days, diseases can be uncovered

Rapid gene-maps for newborns promise to cut diagnosis times to 2½ days for many dangerous genetic ailments, researchers reported on Wednesday.

Such gene maps, or “whole genome” sequences, take months now, too late or delaying treatment for many infants suffering congenital ailments that kill around 5,300 babies yearly, more than 20 percent of infant deaths nationwide.

The pilot study, at Children’s Mercy Hospital in Kansas City, Mo., reports diagnosis of genetic diseases in 50 hours’ time. The study mapped the genes of infants with both known and unknown deadly illnesses.

“For a decade there has been a lot of talk about seeing the human-genome effort pay off not just in research, but in actually having an impact on human health. We may be seeing it happen here,” says National Institute of Child Health and Human Development chief Alan Guttmacher, who was not part of the research. “This is an important proof-of-principle study that needs to be confirmed and repeated by other researchers, but it looks promising.”

In a study reported in the Science Translational Medicine journal, a genome sequencing team led by Carol Saunders of Children’s Mercy Hospital tested rapid genetic diagnosis on two infants with known genetic ailments and four suffering unknown ones, three of whom died at the hospital. Scientists can detect about 3,700 mutations known to cause congenital illnesses, but the rapid test looked for 591 well-understood ones to speed diagnosis. All states must now test newborns for 21 common genetic afflictions, such as the brain-damaging ailment PKU.

In the pilot study, researchers genetically mapped six ill babies, confirming the two known cases and finding diagnoses for three of the four unknown cases, as well as the older brother of one child. The ailments had killed three of those children in the unknown diagnosis cases.

“We think this is going to transform the world of neonatology,” says study co-author Steven Kingsmore of Children’s Mercy Hospital, noting the potential for more information and genetic counseling for parents with desperately ill infants, as well as speeding treatment to sick babies. “Until now, they really had to practice medicine blindfolded,” Kingsmore said.

The approximately $7,000 test relies on computer diagnostics and a rapid gene sequencing machine made by the San Diego-based Illumina Inc., which partly funded the study. The test costs less than one night in a neonatal intensive care unit, Kingsmore says, which should make its promise of faster treatment attractive to insurers.

“Insurers will need to run the numbers, but the way that gene sequencing costs are dropping, by the time you finish the calculation, the costs will have dropped again,” says Guttmacher, who predicts such gene maps will cost $1,000 within the next few years. “One can imagine the day that 99 percent of newborns will have their genomes sequenced immediately at birth.”